Compressor



March 8, 1966 A. FRANK ETAL COMPRESSOR 3 Sheets-Sheet 1 Filed Feb. 5, 1964 INVENTORS ARNE FRANK JEROME QRCACH CARL F. SPE'CH FIG.I

ATTORNEYS A March 8, 1966 A. FRANK ETAL 3,239,132

COMPRESSOR Filed Feb. 5, 1964 5 Sheets-Sheet 2 I32 I20 I30 II8 F/GZ INVENTORS ARNE FRANK JEROME C.ROACH BY CARL F. SPEICH ATTORNEYS March 8, 1966 A. FRANK ETAL COMPRESSOR 3 Sheets-Sheet 5 Filed Feb. 5, 1964 I N VENTO R S A T T O R N E Y S United States Patent 3,239,132 COMPRESSOR Arne Frank, La Crosse, Wis., Jerome C. Roach, Pocatello,

Idaho, and Carl F. Speich, La Crescent, Minn, as-

signors to The Trane Company, La Crosse, Wis., a corporation of Wisconsin Filed Feb. 3, 1964, Ser. No. 342,163 12 Claims. (Cl. 230-58) This invention relates to compressors and more particularly to hermetically sealed motor driven refrigerant compressors of the reciprocating type.

It is a prime object of this invention to provide a motorcompressor unit of extremely compact design, the thickness of which is reduced to a minimum.

It is another object of this invention to provide compressor mechanism of unique pancake design.

A further object of this invention is to provide a motor driven compressor having a novel cooling arrangement for the motor.

A still further object of this invention is to provide the motor enclosure of a motor-compressor unit with a cooling fluid inlet on the compressor end in an area unobstructed by the cylinders of the compressor.

Another object of this invention is to provide a four cylinder compressor of the pancake configuration wherein a two-throw crankshaft is employed having one throw displaced from the other by an angle of 90".

A further object of this invention is to provide a compressor motor cooling means whereby a single thermal sensing device may be employed to accurately sense excessive motor temperatures for both running and locked rotor conditions.

Still another object of the invention is to provide a motor-compressor unit having a pancake compressor with a hermetic casing of elliptical configuration.

Other objects and advantages will become apparent as this specification proceeds to described the invention with reference to the accompanying drawings in which:

FIGURE 1 is a side elevation of the compressor unit, the outer casing being sectioned to reveal the interior thereof, and a head of the compressor mechanism therein removed to more clearly show fluid passages;

FIGURE 2 is a section taken at line 22 of FIG- URE 1;

FIGURE 3 is a section taken approximately at line 3-3 of FIGURE 1; and

FIGURE 4 is an enlarged bottom end view of the crankshaft employed in the compressor of the proceding figures.

Now referring to the drawing, it will be seen that compressor is provided with a hermetic outer casing 12 having cylindrical side walls of generally elliptical configuration as viewed in FIGURE 3. A fluid inlet 14 and fluid outlet 16 are arranged in the convex-upward top of casing 12. Casing 12 may be constructed by joining an upper and a lower shell, one of which has a peripheral lip for receiving the other shell as at 18. The casing may thus be hermetically sealed to the exterior except through inlet 14 and outlet 16 as by welding or any other suitable means. Fastened within the casing 12 at the bottom thereof are a plurality of mounting brackets 20 upon which a motor-compressor unit 22 is resiliently supported as by lower mounting springs 24. The motorcompressor unit mounting may also include a downwardly facing spring receiving cup 26 joined to the interior top side of casing '12 for receiving upper mounting spring 28.

The motor-compressor unit is comprised of a compression mechanism 30 and an electric motor 32 mounted above said compression mechanism. The motor-compressor unit includes a main body 34 having upwardly extending annular side wall 36 for receiving an electric motor "ice 32, a generally horizontal partition 38 at the bottom of said annular wall separating motor 32 from compression mechanism and a compressor body 40 defining a compressor crankcase 42 with a pair of parallel horizontally extending radial cylinder boxes 44 arranged on diametrically opposite sides of said crankcase. Each pair of cylinders forms a bank of cylinders.

A vertically extending bore 46 in partition 38 is provided with a sleeve bearing 48. Concentric with bore 46 is a second bore 50 in lower bearing support member 52 connected to the bottom of the crankcase 42 as by volts 54. A sleeve bearing 56 is disposed in bore 50 and receives the lower journal 58 of vertically extending compressor crankshaft 60 which has an upper journal 62 mounted for rotation in sleeve bearing 48.

The main body 34 rests directly on lower mounting springs 24 and may be provided with locating pins 64 which extend centrally of each of said springs to prevent undue lateral shifting of the lower portion of the motorcompressor unit relative to casing '12.

Located between journals 58 and 62 on crankshaft 60 are first and second crank throws 66 and 68 respectively which are angularly displaced from each other about the crankshaft axis of rotation by an angle of 90 as will be seen more clearly in FIGURE 4.

If desired bores 44 may be provided with cylinder sleeve inserts 70. The piston 72 is reciprocally mounted in each of the compression cylinders thus formed and is connected to a throw of the crankshaft 60 by a connecting rod 74.

The connecting rods associated with the upper cylinder of each pair or bank of cylinders are connected to the first or upper throw 66 of crankshaft 60. The connecting rods associated with the lower cylinder of each pair or bank of cylinders are connected to the second or lower throw 68 of crankshaft 60. The cylinder bores of one bank of cylinders may be slightly offset from the bores of the opposing bank of cylinders in the direction of the crankshaft axis to facilitate the mounting of two connecting rods on each crankshaft t-hrow.

Crankshaft 60 may be provided with counterweights 76 to facilitate balancing as desired.

Now referring to thestructure of motor 32 it will be seen that crankshaft 69 has an end portion 78 of reduced diameter located above journal 62 and upon which rotor 80 may be drivingly mounted for rotation therewith as by key 82 arranged in suitable grooves in the rotor and crankshaft. Circumscribing rotor 88 is a motor stator 84 having upper and lower end turns 86 and 88 extending above and below rotor 80 respectively. Stator 84 may be mounted in the socket formed by annular side wall 36 in any desired manner such as by press fitting, etc. However, it is preferred that adequate space be provided between stator 84 and annular side wall 36 to permit the passage of sufficient cooling gas as will hereinafter be explained. This may be accomplished by providing a plurality of vertically extending grooves 90 on the inner surface of annular wall 36. A generally concave-downward motor cover 92 extends over the motor and downward into sealing engagement with the upper portion of annular side wall 36 at 93. The combination of partition 38, anular side wall 36 and motor cover 92 form a motor compartment encapsulating motor 32 in a fluid enclosure which functions as a shroud to guide cooling suction gas over and through the motor as will hereinafter be described.

At the bottom wall of the motor compartment in partition 38 is a pair of motor compartment fluid inlet apertures 94 disposed on opposite sides of bearing 48 angularly between the cylinder banks. One such aperture is fully shown in FIGURE 3. At the center of cover 92 is a motor compartment fluid outlet 96. Disposed within the motor compartment between the upper end turns 86 of motor stator 84 adjacent the upper end of rotor 86 is arranged a suction muflier 98 in fluid communication with fluid outlet 96 and the interior of the motor compartment. A centrifugal oil separator 100 may be mounted in close proximity to mufller 98 and drivingly connected to rotor 86 as by bolt 182.

In operation suction gas entering casing inlet 14 passes downward to enter motor compartment fluid inlet apertures 94 adjacent bearing 48, passes upward through the gap between rotor and stator 84 and through grooves to oil separator 100 and mufiier 93 to the motor compartment fluid outlet 96.

It will be noted that the suction gas first passes in close proximity to bearing 48 and then moves upward to cool the upper stator end turns 86.

A thermal responsive motor protective cut-out switch 104 connected in series with the stator winding is placed in heat exchange relation with the upper end turns. Since the suction gas is first directed to the vicinity of bearing 48 adjacent lower end turns 88 and then to the upper end turns 86, the upper end turns present a higher temperature than the lower end turns 88 for both running and and locked rotor conditions.

In prior art compressors, the lower end turns would tend to become warmer than the upper end turns during running conditions as a result of the heat generated at the crankshaft journal bearing. On the other hand the upper end turns would become warmer under locked rotor conditions as the heat would gravitate to the upper portions of the motor and no heat would be generated at the hearing. This obviously complicated the problem of sensing motor overheat. With our novel cooling arrangement this problem is eliminated as the upper end turns become the warmest for both running and locked rotor conditions.

The suction gas is led from motor compartment outlet 96 to a pair of side suction mufflers 166 by a pair of conduits 198 which are generally rectangular in cross-section as will be evident from FIGURES l and 2. Conduits 108 and side mufllers 106 lie on opposite sides of the crankshaft 69 in the plane passing through both banks of cylinders. This arrangement permits the compressor to be constructed with a minimum thickness in the direction normal to this plane.

Mounted on the upper side of the structure of conduits 108 concentrically with the axis of crankshaft 69 is an upwardly extending annular flange 110 for receiving the lower end of mounting spring 28 aforementioned for supporting the motor-compressor unit at the upper end thereof within outer casing 12.

Each side suction muffler may be partially cast as an integral part of the compressor main body 34 and has a suction muffler outlet 112 in fluid communication with a suction manifoldportion 114 of main body 34 which surrounds each cylinder of a cylinder bank. The suction manifold portion 114 provides fluid communication between its respective suction mufller outlet 112 and the inlet ports 116 of each valve assembly 113 disposed at the end of each cylinder remote from crankshaft 69.

A combined muflier and cylinder head 12.0 is provided for each bank of cylinders. A portion 122 of head is provided with recesses 124 which cooperate with recesses 126 in the muflier portion of main body 34 to form a plurality of muflier chambers interconnected by relatively small passages 127. Cylinder head 120 may have recesses 128 for cooperation with the suction manifold portion 114 of the main body to form a complete suction manifold. A sealing gasket (not shown) may be placed between the mutflencylinder head 120 and main body 34.

Cylinder head 120 also has a recess 130 at the end of each cylinder of its respective cylinder bank. Reccsses 130 are sealed from the suction manifold passages by a valve assembly 118 and receive gas discharged from discharge ports 132 of said valve assembly. Each recess 135) of both cylinder banks communicates via a passage 134 in the cylinder head with a discharge manifold inlet passage 4 136 of discharge manifold 138 (FIGURE 3) which extends across one side of crankcase 42. The discharge manifold 138 is preferably integrally cast with the compressor main body 34 and is located on the side of crankcase 42 opposite from crankcase access opening 140 having a removable closing member 142.

The gas collected in the discharge manifold from all cylinders passes into inlet 144 of discharge mufller 146. Muffler 146 includes a perforated tube 148 extending between inlet 144 and discharge chamber 150. The perforations in tube 143 communicate with a closed acoustic side branch chamber 152 which may be proportioned to attenuate certain sound frequencies. Tube 148 may be positioned in the desired location by insertion through an aperture in main body 34 which is subsequently closed by plug 154. In order to avoid complex coring it is preferable to cast the discharge muffler and manifold with open chambers which are subsequently closed by a discharge manifold and mufller cover 156 as by bolts 157. Discharge chamber communicates with discharge conduit 158 which has a resilient loop partially encircling the motor portion connected to the outer casing fluid outlet 16.

It will be understood that by reason of the crankshaft throw and cylinder arrangement, a cylinder discharges gas into the discharge manifold 138 at even intervals of 90". Sound generated by this uniform discharge frequency is more easily dampened by discharge muffler 146 proportioned to attenuate sounds associated with the uniform discharge frequency. Another advantage which results from this crankshaft cylinder arrangement is that owing to the even spacing of the discharge pulses, the stress in the crankshaft and bearings is kept to a minimum which permits the use of smaller parts and makes for more compact construction.

In order that connecting rods 74 may be disconnected from crankshaft 60 through access aperture 140 it will be noted that the connecting rod bearing at the crankshaft end of each connecting rod is split along a plane which is inclined from the connecting rod longitudinal axis toward the access opening. Suitable bolts 160 hold the cap portion of the bearing to the main portion of the connecting rod. All bolts 160 are easily accessible through the single opening 140.

Since all electrical and fluid connections are made to the compressor casing on the top side, it is extremely easy to insert the compressor into a sound or heat insulating jacket or into an annular heater as may be desired for reasons well recognized by those having skill in the art.

The compressor hereinabove described presents an extremely compact package which provides adequate cooling and protection for the drive motor of the motorcompressor unit resiliently supported within the outer casing. The novel crankshaft, cylinder and muffler arrangements are extremely'suitable both from the standpoint of compactness and sound attenuation.

Although we have described in detail the preferred embodiment of our invention, we contemplate that many changes may be made without departing from the scope or spirit of the invention and we therefore desire to be limited only by the claims.

We claim:

1. A compressor comprising the combination of a hermetic casing; said casing having a fluid inlet and a fluid outlet; a compression mechanism mounted within said casing; 21 motor mounted within said casing and drivingly connected to said compression mechanism; and means within said casing forming a fluid enclosure about said motor; fluid inlet means for admitting cooling suction gas to said enclosure at the end of said enclosure adjacent said compression mechanism; means forming a fluid outlet from said enclosure at an end remote from said compression mechanism; means for conducting a major portion of the fluid entering said casing fluid inlet to said fluid inlet means; and conduit means providing fluid communication between the discharge side of said compression mechanism to the fluid outlet in said casing.

2. A compressor comprising the combination of a hermetic casing; a compression mechanism mounted within said casing having an elongated crankshaft; a motor mounted within said casing drivingly connected to said crankshaft; means within said casing forming a fluid enclosure about said motor; a partition extending between said motor and compression mechanism forming a portion of said fluid enclosure; said compression mechanism encompassing a portion of said partition; a fluid inlet to said enclosure disposed in that portion of said partition unencompassed by said compression mechanism; a fluid outlet from said fluid enclosure at the end of said fluid enclosure remote from said compressor mechanism; conduit means connecting the fluid outlet of said enclosure to the suction side of said compression mechanism; and means forming a fluid inlet and a fluid outlet in said casing.

3. A compressor comprising the combination of a hermetic casing; an elongated crankshaft mounted for rotation about its longitudinal axis and disposed entirely within said casing; a pancake compression mechanism entirely within said casing drivingly connected to one end portion of said crankshaft and a motor entirely within said casing drivingly connected to the other end of said crankshaft; said compression mechanism having a first bank of right circular compression cylinders on one side of said crankshaft and a second bank of right circular compression cylinders on the opposite side of said crankshaft; piston means in the cylinders of each bank of cylinders; and means connecting said piston means to said crankshaft; said hermetic casing having a generally elliptical cross-section in a plane extending through said banks of cylinders normal to said longitudinal axis; the major dimension of said elliptical crosssection being substantially in an imaginary plane passing through said longitudinal axis and both banks of cylinders.

4. The apparatus as defined by claim '3 wherein means is provided for encapsulating said motor in a motor compartment; said motor compartment having a fluid inlet at the end portion closest said compression mechanism and a fluid outlet at the end portion remote from said compression mechanism; a first fluid conduit extending from said motor compartment fluid outlet at one side thereof to a suction manifold for one of said banks of cylinders and a second fluid conduit extending from said motor compartment fluid outlet at the opposite side thereof to a suction manifold for the other bank of cylinders; said first and second fluid conduits extending generally parallel to said imaginary plane; said casing having a generally elliptical cross-section in a plane extending through said motor and conduits normal to the longitudinal axis of said crankshaft; the major dimension of said last mentioned elliptical cross-section being substantially in said imaginary plane.

5. The apparatus as defined by claim 4 wherein said first and second fluid conduits each include a suction muffler.

6. A compressor comprising the combination of a hermetic casing; a compression mechanism in said casing; a motor in said casing drivingly connected to said compression mechanism; said compression mechanism having a plurality of banks of cylinders; means encapsulating said motor in a motor compartment; said motor compartment having a fluid inlet at the end portion closest said compression mechanism and a fluid outlet at the end portion remote from said compression mechanism; a fluid conduit connecting the suction side of each bank of cylinders to said compartment fluid outlet; a suction muflier disposed in each of said fluid conduits; a suction muffler disposed adjacent said compartment fluid outlet upstream of all of said muiflers in said fluid conduits; means forming a fluid inlet in said casing; means forming a fluid outlet in said casing; and means providing fluid communication from the discharge side of said compression mechanism to the fluid outlet in said casing.

7. A compressor comprising in combination a hermetic casing; a fluid inlet and a fluid outlet in said casing; a compression mechanism mounted within said casing; a motor mounted within said casing above said compression mechanism; means within said casing forming an enclosure about said motor; said enclosure having a bottom wall; a vertically extending crankshaft extending through said bottom wall and drivingly connecting said compression mechanism to said motor; bearing means supported by said bottom wall for rotatably mounting said crankshaft; said motor comprising a rotor mounted on the upper portion of said crankshaft for rotation therewith and a stator circumscribing said rotor having upper and lower end turns; means for conducting a major portion of the fluid entering said fluid inlet to a zone within the lower portion of said enclosure adjacent said bearing means and said lower end turns; means for conducting fluid delivered to the lower portion of said enclosure to the upper portion of said enclosure; conduit means for providing fluid communication from the upper portion of said enclosure adjacent the upper end turns to the suction side of said compression mechanism; and a temperature responsive switch means operatively connected to said motor and responsive to the temperature in the upper portion of said enclosure for de-energizing said motor under excessive thermal loads for both running and locked rotor conditions.

8. A compressor mechanism comprising an elongated crankshaft mounted for rotation; two banks of compression cylinders disposed in substantially a common plane; each bank of cylinders being arranged on a side of said crankshaft opposite from the other bank; a crankcase extending between the banks of cylinders for housinga portion of said crankshaft; a manifold for both of said banks of cylinders disposed on one side of said crankcase laterally of said crankshaft; and a crankcase access means arranged in said crankcase on the side of said crankcase opposite from said manifold; piston means in said cylinders and means connecting said piston means to said crankshaft, said access opening permitting the assembly of said connecting means of both banks of cylinders to said crankshaft, said means connecting said piston means to said crankshaft including at least one elongated connecting rod having a split bearing at the crankshaft end; said split bearing including a rod portion and a cap portion; a major portion of said cap portion being disposed on the side of the longitudinal axis of said connecting rod adjacent said access means.

9. A compressor comprising a crankshaft mounted for rotation about an axis; a first right circular cylinder; a second right circular cylinder adjacent and substantially parallel to said first cylinder; said first and second cylinders being arranged on one side of said crankshaft; a third right circular cylinder; a fourth right circular cylinder adjacent and substantially parallel to said third cylinder; said third and fourth cylinders being arranged on a side of said crankshaft opposite said first and second cylinders; a piston reciprocally mounted in each of said cylinders; saidcrankshaft having a first throw and a second throw; said first throw being angularly displaced from said second throw in such a manner that a plane containing said first throw and said axis of rotation is substantially normal to a plane containing said second throw and said axis of rotation; means connecting the pistons in said first and third cylinders to said first throw and means connecting each throw to pistons disposed in each cylinder to said second throw.

10. A four cylinder pancake compressor comprising an elongated crankshaft mounted for rotation about its longitudinal axis; a first pair of substantially parallel right circular cylinders disposed on one side of said crankshaft; a second pair of substantially parallel right circular cylinders disposed on a side of said crankshaft opposite said first pair of cylinders; a piston slidably mounted within each of said cylinders; said crankshaft having first and second crankthrows; said first throw being angularly displaced from said second throw by an angle of substantially 90 about said crankshaft longitudinal axis; and means connecting each throw to piston disposed in each pairs of cylinders.

11. A pancake compressor comprising a crankshaft mounted for rotation about an axis; a cylinder means arranged on opposite sides of said crankshaft; each of said cylinder means comprising at least one right circular cylinder having a central axis of generation; the central axes of said cylinder means and said axis of rotation substantially lying in a common plane; the cylinder means on one side of said crankshaft having a plurality of said cylinders and at least as many cylinders as the cylinder means on the other side of said crankshaft; said crankshaft having a number of throws equal to the number of cylinders on said one side; piston means arranged in each of the above defined cylinders; means connecting at least all but one of said throws to a piston means in a cylinder means on each side of said crankshaft; and said throws being angularly displaced about said axis of rotation by an angle of about 180 divided by the number of cylinders on said one side.

12. A compressor comprising the combination of a hermetic casing; a compression mechanism in said cas ing; a motor in said casing drivingly connected to said compression mechanism; means encapsulating said motor in a motor compartment; said motor compartmenthaving a fluid inlet at the end portion closest said compression mechanism and a fluid outlet at the end portion remote from said compression mechanism; a fluid conduit connecting the suction side of compression mechanism to said compartment fluid outlet; a suction mutfier disposed in said fluid conduit; means forming a fluid inlet in said casing; means forming a fluid outlet in said casing; and means providing fluid communication from the discharge side of said compression mechanism to the fluid outlet in said casing.

References Cited by the Examiner UNITED STATES PATENTS 2,005,107 6/1935 Phillips et al 103-171 2,139,996 12/1938 Buchanan 23 0208 2,500,751 3/1950 Halfvarson 230208 2,622,788 12/1952 Ramclow 23058 2,668,004 2/ 1954 Browne 23058 3,044,682 7/1962 Weibel et a1. 23058 3,044,688 7/1962 Frank et a1 230232 3,101,891 8/1963 Frank 230232 FOREIGN PATENTS 951,257 10/ 1956 Germany.

ROBERT M. WALKER, Primary Examiner. 

1. A COMPRESSOR COMPRISING THE COMBINATION OF A HERMETIC CASING; SAID CASING HAVING A FLUID INLET AND A FLUID OUTLET; A COMPRESSION MECHANISM MOUNTED WITHIN SAID CASING; A MOTOR MOUNTED WITHIN SAID CASING AND DRIVINGLY CONNECTED TO SAID COMPRESSION MECHANISM; AND MEANS WITHIN SAID CASING FORMING A FLUID ENCLOSURE ABOUT SAID MOTOR; FLUID INLET MEANS FOR ADMITTING COOLING SUCTION GAS TO SAID ENCLOSURE AT THE END OF SAID ENCLOSURE ADJACENT SAID COMPRESSION MECHANISM; MEANS FORMING A FLUID OUTLET FROM SAID ENCLOSURE AT AN END REMOTE FROM SAID COMPRESSION MECHANISM; MEANS FOR CONDUCTING A MAJOR PORTIONS OF THE FLUID ENTERING SAID CASING FLUID INLET TO SAID FLUID INLET MEANS, AND CONDUIT MEANS PROVIDING 